The discovery of plastics as useful materials for human existence, providing comfort and ease has now turned into a menace in the society and a pain in the neck as plastics have also become co-habitat of the human ecosystem. Plastics were made by men, but plastics now live way longer than the men who gave them the privilege of existence. Since these colonies of materials cannot be eradicated, it is very pertinent to discover possible ways of useful diversion through recycling by converting plastic bottle waste into useful raw materials for other sectors of the economy. This paper has stirred the pool of relevant literature to extract some of the innovative efforts that have been deployed into redirecting the potential of plastic waste into useful applications like engineering and building construction, horticulture in agriculture, and the most advanced application is the 3D printing using plastics as filaments. Following the trend of technology, 3D printing is a grey area of plastic recycling, it is quite expensive however, it worth exploring.

The cement manufacturing industry has played a fundamental role in global economic development, but its production is a major facilitator to anthropogenic CO₂ release and solid waste generation. Nigeria has the largest cement industry in West Africa, with an aggregate capacity of 58.9 million metric tonnes (MMT) per year. The Ministry for Mines and Steel Development asserts that the nation possesses total limestone deposits of around 2.3 trillion MT with 568 MMT standing as established reserves and 11 MMT used. Cement industries are largely responsible for releasing air pollutants and effluents into water bodies with apparent water quality deterioration over the years. Air pollution from lime and cement-producing plants is seen as a severe instigator of occupational health hazards and work-related life threats, negatively affecting crop yields, buildings, and persons residing in the vicinity of these industries. World Bank observed in 2015 that 94% of the Nigerian populace is susceptible to air pollutants that surpass WHO guidelines. In 2017, World Bank further reported that 49,100 premature deaths emanated from atmospheric PM_2.5, with children beneath age 5 having the greatest vulnerability owing to lower respiratory infections, thereby representing approximately 60% of overall PM_2.5-induced deaths. Cement manufacturing involves the significant production of SO₂, NO_x, and CO connected to adverse health effects on humans. Sensitive populations such as infants, the aged, and persons having underlying respiratory ailments like asthmatics, emphysema, or bronchitis are seen to be most affected. Consequently, in addressing this challenge, growing interests in enacting carbon capture, usage, and storage in the cement industry is expected to alleviate the negative environmental impact of cement production. Still, no carbon capture technology is yet to achieve commercialization in the cement industry. Nonetheless, huge advancement has been made in recent years with the advent of vital research in sorption-enhanced water gas shift, underground gasification combined cycle, ammonium hydroxide solution, and the microbial-induced synthesis of calcite for CO₂ capture and storage, all considered sustainable and feasible in cement production.

The impact of plastic pollution on the world and its inhabitants is yet to be fully measured. Significant quantities of microplastics and nanoplastics have been found in human organs, and many diseases have been traced to their presence. Even human placentas have been found to contain microplastics. This study examines the recycling landscape, advanced reprocessing techniques, and technical challenges in this industry. It points out the top recyclable types of plastics (such as high-density polyethylene, polyethylene terephthalate, and thermoplastic elastomers) by analyzing their different recycling capacities globally. It highlights the most advisable recycling techniques by identifying those most successful, least environmentally damaging, and easiest. Mechanical recycling is arguably the easiest and most common recycling technique. This study examines mechanical reprocessing technologies for construction materials, composite boards, additive manufacturing, and other applications. It also points out prevailing setbacks of these approaches and analyzes different solutions. Promising recycling processes are suggested for further investigation.

Solar and wind power systems have been prime solutions to the challenges centered on reliable power supply, sustainability, and energy costs for several years. However, there are still various challenges in these renewable industries, especially regarding limited peak periods. Solar–wind hybrid technology introduced to mitigate these setbacks has significant drawbacks and suffers from low adoption rates in many geographies. Hence, it is essential to investigate the challenges faced with these technologies and analyze the viable solutions proposed. This work examined solar–wind hybrid plants’ economic and technical opportunities and challenges. In the present work, the pressing challenges solar–wind hybrids face were detailed through extensive case studies, the case study of enabling policies in India, and overproduction in Germany. Presently, the principal challenges of solar–wind hybrids are overproduction, enabling policies, and electricity storage. This review highlights specific, viable, proposed solutions to these problems. As already recorded in the literature, it was discovered that academic research in this space focuses majorly on the techno-economic and seemingly theoretical aspects of these hybrid systems. In contrast, reports and publications from original equipment manufacturers (OEMs) and engineering, procurement, and construction engineers (EPCs) are more rounded, featuring real-life application and implementation.

Titanium (Ti) alloys have been employed for several structural purposes due to high strength, lightweight, temperature toughness, outstanding corrosion resistance and extreme temperature tolerance ability. However, their application for aircraft, military equipment and spacecraft etc. is limited by the exorbitant cost of raw materials and processing. Although, commercially unadulterated titanium exhibits satisfactory mechanical characteristics and has been used for some engineering applications. For many applications, titanium is combined or alloyed with little percentages of alloying elements such as vanadium and aluminium by weight. The combination possesses solid solubility which differs with temperature, enabling it to experience precipitation strengthening. This strengthening effect and effect of heat treatment does not only affect the mechanical and structural properties but alters the tribological and corrosion resistance (CR) properties of the alloys. The CR property of alloys is vital in any structural application and this affects other properties directly or indirectly. Therefore, this review paper examines the properties, classification and applications of Ti and its alloys.